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<h2><a name="SECTION0051110000000000000000"></a><a name="typesmodules"></a>
<br>
3.11.1 Modules 
</h2>

<p>
The only special operation on a module is attribute access:
<code><var>m</var>.<var>name</var></code>, where <var>m</var> is a module and <var>name</var>
accesses a name defined in <var>m</var>'s symbol table.  Module attributes
can be assigned to.  (Note that the <tt class="keyword">import</tt> statement is not,
strictly speaking, an operation on a module object; <code>import
<var>foo</var></code> does not require a module object named <var>foo</var> to exist,
rather it requires an (external) <em>definition</em> for a module named
<var>foo</var> somewhere.)

<p>
A special member of every module is <tt class="member">__dict__</tt>.
This is the dictionary containing the module's symbol table.
Modifying this dictionary will actually change the module's symbol
table, but direct assignment to the <tt class="member">__dict__</tt> attribute is not
possible (you can write <code><var>m</var>.__dict__['a'] = 1</code>, which
defines <code><var>m</var>.a</code> to be <code>1</code>, but you can't write
<code><var>m</var>.__dict__ = {}</code>).  Modifying <tt class="member">__dict__</tt> directly
is not recommended.

<p>
Modules built into the interpreter are written like this:
<code>&lt;module 'sys' (built-in)&gt;</code>.  If loaded from a file, they are
written as <code>&lt;module 'os' from
'/usr/local/lib/python2.5/os.pyc'&gt;</code>.

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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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